1. Field of the Invention
This invention relates to a matrix-addressed type liquid crystal display device such as a liquid crystal television or a liquid crystal display for use in a laptop personal computer.
2. Description of the Related Art
With the progress of information-oriented society, a rapid advancement has been made in the field of matrix-addressed type display devices such as a liquid crystal display and the like.
FIG. 8 of the accompanying drawings shows a driver circuit of a conventional liquid crystal display. In FIG. 8, reference numerals X.sub.1 to X.sub.m designate a plurality of column line data electrodes, to which a data voltage is applied from a data output circuit 1, spaced from each other in parallel; and Y.sub.1 to Y.sub.n designate a plurality of row line scanning electrodes, to which a scanning voltage is applied from a scanner circuit 2, spaced from each other in parallel. A thin film transistor (hereinafter called TFT) is formed at each intersection of a column line pattern of the data electrodes X.sub.1 to X.sub.m with a row line pattern of the scanning electrodes Y.sub.1 to Y.sub.n. A gate electrode 4 of a TFT 3 formed along an i-th line, where i represents an integer from 1 to n, is electrically conducted to a row line scanning electrode Yi. A source electrode 5 of the TFT 3 formed along a j-th line, where j represents an integer from 1 to m, is electrically conducted to a column line data electrode Xj. To a drain electrode 6 is a pixel electrode 7 electrically conducted. At a position confronting to the pixel electrode 7 is an opposing electrode 8 formed, and liquid crystal 9 is sandwiched between the opposing electrode 8 and the pixel electrode 7.
The liquid crystal display device having the foregoing structure is driven in sequence as described below. Initially, the scanner circuit 2 outputs a scanning voltage to one of the scanning electrodes Y.sub.1 to Y.sub.n, so that the scanning voltage is applied to gate electrodes of all TFTs positioned in the same row to turn the TFTs 3 on. In synchronization with the application of the scanning voltage to any row, the data output circuit 1 supplies a data voltage to every pixel by way of the data electrodes X.sub.1 to X.sub.m, and this video signal voltage is then transferred to one pixel electrode 7 only by way of the TFT 3 whose gate is being applied with the scanning voltage. When the application of the scanning voltage shifts to a subsequent row, the TFT 3 having been activated is turned off and electric charges are then stored in liquid crystal 9 of that TFT 3. Thus, displaying is effected on that liquid crystal 9.
However, in the case of the driver circuit having the above-described configuration for used in the liquid crystal display, a breakage of the pattern in either the scanning electrodes Y.sub.1 to Y.sub.n or the data electrodes X.sub.1 to X.sub.m results in the interruption of the voltage transfer at a broken spot and hindering a further transmission of the voltage. In result, a line-shape defect develops on the display screen composed of liquid crystals 9 arranged in the matrix. A method of recovering from such a line defect on the liquid crystal display is disclosed in Japanese Patent Laid-Open Publication No. 15990/1989.
FIG. 9 is a wiring diagram showing a liquid crystal display disclosed in the above-described Japanese publication. In FIG. 9, a rectangular area, surrounded by dotted lines and having corners specified with A, B, C and D, is composed of a plurality of display elements, that is, pixels and serves as a display area on which an image is produced. Z designates a conductor pattern pair which is subdivided into four fractional pairs Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4 and is arranged so as to enclose the outer most periphery of the display area with the corners A, B, C and D and serves for restoring a broken pattern. This recovery conductor pattern pair intersects with the data electrodes X.sub.1 to X.sub.m, and the scanning electrodes Y.sub.1 to Y.sub.n via a non-illustrated dielectric layer. This recovery conductor pattern pair Z has bonding pads 21 for interconnecting spatially pattern fractional pairs Z.sub.1 through Z.sub.4 with each other. 22 designates a wire bonding pattern for interconnecting the recovery conductor pattern pair Z with either a row line of the scanning electrodes Y.sub.1 to Y.sub.n or a column line of the data electrodes X.sub.1 to X.sub.m ; and 22b, a wire bonding pattern for interconnecting together the fractional recovery conductor pattern pairs Z.sub.1 through Z.sub.4 spaced from each other.
A pattern breakage recovery according to a conventional method will be described with the assumption that the row line scanning electrode Y.sub.1 has a breakage at a spot designated by X. In such a case, as shown in FIG. 9, if the row line scanning electrode Y.sub.1 is connected to both the fractional recovery conductor pattern pairs Z.sub.1 and Z.sub.2, respectively, by means of the wire bonding 22, and also if these fractional recovery conductor pattern pairs Z.sub.1 and Z.sub.2 are interconnected with each other by means of a wire bonding wiring 22b, an alternate conductive path of the broken row line electrode Y.sub.1 is made. By this alternate conductive path, the voltage can be transmitted further from the broken spot, thereby restoring the pattern defect.
FIG. 10 is a cross-sectional plan view of the liquid crystal panel taken along the row line scanning electrode Y.sub.1 of FIG. 9 at the corner B, where 20 designates a matrix-addressed substrate; 22, an opposing substrate; 23, a liquid crystal layer; and 27, sealing material.
Since the conventional matrix-addressed liquid crystal device having the above structure, the matrix-addressed substrate 20 projects from edges of the opposing substrate 22 with respect to the display area, i.e., top, bottom, left and right sides as shown in FIG. 10. Accordingly, in order to feed liquid crystal into a cell, a reservoir 30 for storing liquid crystal must have a depth exceeding the length of the projecting portions of the matrix-addressed substrate 20 as illustrated, which resulted in increasing the amount of expensive liquid crystal to be used. Moreover, since all of the projecting portions of the matrix-addressed substrate 20 are immersed into liquid crystal layer 31 in the liquid crystal reservoir, the liquid crystal 31 is contaminated by impurities existing on the surface of the matrix-addressed substrate 20, namely, deterioration in a resistivity of the liquid crystal is caused, thereby disadvantageously shortening the estimated usable period of the liquid crystal 31. Since the liquid crystal to be used in the liquid crystal display is expensive, it is impossible to reduce the cost of the matrix-addressed type liquid crystal device.